adding comments for this fix

cmake/generic.cmake

@@ -587,6 +587,9 @@ function(grpc_library TARGET_NAME)
   get_filename_component(PROTO_WE ${grpc_library_PROTO} NAME_WE)
   get_filename_component(PROTO_PATH ${ABS_PROTO} PATH)
 
+  #FIXME(putcn): the follwoing line is supposed to generate *.pb.h and cc, but
+  # somehow it didn't. line 602 to 604 is to patching this. Leaving this here 
+  # for now to enable dist CI.
   protobuf_generate_cpp(grpc_proto_srcs grpc_proto_hdrs "${ABS_PROTO}")
   set(grpc_grpc_srcs "${CMAKE_CURRENT_BINARY_DIR}/${PROTO_WE}.grpc.pb.cc")
   set(grpc_grpc_hdrs "${CMAKE_CURRENT_BINARY_DIR}/${PROTO_WE}.grpc.pb.h")